Another Small Nuisance

I have just finished writing on track X. I want to write on track Y. So, I select track Y, make sure that there is a region in place on track Y, then select "all" so that all notes will show in the piano roll. Now, every note I write on a completely different track instead of track Y. Of course, if I select only track Y, with no regions on any other  tracks, the new notes are on the proper track, and will be after I select "all". 

This is apparently a recent Logic innovation. 

I could not duplicate that.  Followed your steps exactly.  The notes I entered on the second track, appeared only on the second track.  To repeat:

1) created a new track, added a region, entered some notes.

2) created a second track, added a region.

3) selected the second track, it's region appeared in the editor.

4) used cmd-A to select all (track 1's data appeared)

5) entered some notes.

Now when I view each track, I see the correct notes for each track.

Am I missing something?

Mystified. Now, I can't reproduce it, either. It's something that happens quite a lot. If it's something I'm doing, it's a little bit of a habit. I may never know.

Was the editor unlinked? In such a case, selecting another region in the arrange window, won't change the content shown in the piano editor.